Fibre Channel was definitely not top of mind when Chris Brown hit the wall on disk space and, in mid-2005, decided to go shopping for a SAN. Brown is IT manager for DeltaValve, a division of Curtiss-Wright Flow Control. “I have an IT staff of two,” he explains, “and we do not have the resources to support Fibre Channel.”
Instead, Brown opted for the convenience and low cost of an IP-based network storage system. To that end, he bought five NSM 150s from LeftHand Networks as building blocks for a new iSCSI SAN. Each unit comes with four 250GB drives, so he had a cluster of five terabytes of new storage that, unlike a Fibre Channel SAN, would require little in the way of specialized skills to maintain. (See also “The trends that shape iSCSI’s trajectory” and “New choices in networked storage.”)
The value proposition of iSCSI storage has always been its simplicity and low cost compared to Fibre Channel. All you need is capacity on a Gigabit Ethernet network — no special training in an esoteric protocol, just a little education on top of basic networking skills. An iSCSI SAN can also smooth the path to data replication and disaster recovery, especially over long distances. And if speed is an issue, 10GbE (10 Gigabit Ethernet) is already here, if somewhat pricey.
Drue Reeves, research director with the Burton Group, calls the iSCSI SANs from such vendors as LeftHand, DataCore, and FalconStor “software-only targets. They are relatively cheap,” he explains, “because they run on standard hardware. They are powerful because you can cluster them and add storage virtualization on top, so a LUN [logical unit number] can fail over to another target, and the user never knows.”
It was clear that iSCSI had arrived when Microsoft put an initiator in Windows Server 2003. What was not so clear was where iSCSI would go. Fibre Channel still rules the SAN market, and Microsoft didn’t follow suit with an iSCSI target until last year.
But last fall iSCSI got a huge boost when VMware, the hottest name in virtualization, added iSCSI support. To get the most out of virtualization, you need a SAN — and now you can do it without Fibre Channel.
The virtualization connection
DeltaValve’s Brown, who isn’t afraid of getting under the hood, quickly saw the potential of his new SAN. “I moved everything — SQL Server, Navision, SharePoint, Exchange Server, and an Oracle database that runs our PLM (Product Lifecycle Management) System — onto them,” he says.
Brown’s willingness to tinker also took him deep into the world of virtualization. “About three months after we got the SAN running, I brought VMware into the mix. Virtual storage from the SAN and server virtualization from VMware go hand in hand.”
Brown has two host VMware servers (both homegrown, Quad AMD Opteron-powered boxes) and runs eight virtual servers on each. “The beauty,” he says, “is that if one host goes down, we can use the other host to mount the same volume and be up in a matter of minutes.”